An anastomosis is a connection between two anatomical structures. For example, in the course of an organ transplantation, severed blood vessels can be connected with each other by means of anastomoses.
Various methods for producing such anastomoses in surgery are known. The connection can be produced with the use of suturing techniques. Furthermore, there are approaches that allow the organic connection with the use of adhesion techniques. In one example, fibrin sealants are used, thus making possible the highly advantageous connection of organs, in particular hollow organs. However, the tolerability of these sealants or glues is problematic because they may exhibit thrombogenic and toxic properties.
Clamping techniques have also been used to provide a connection at a suitable site. Various aids such as rings, cuffs or stents have been used to aid in producing anastomoses. The disadvantage of these clamping techniques is that they generally remain in the hollow organ to be connected and can trigger rejection reactions and there is also danger of the formation of a thrombus.
From publication WO 03/061487 A1 it is known to connect hollow organs with the application of a suitable high-frequency current (RF current). When the RF current is being applied the tissue structures are being welded together. The cell substance coagulates causing the protein structures to be welded together, so that a controlled, safe, and fast connection can be produced. For the application of the RF current, publication WO 03/061487 A1 describes an instrument comprising an interior sheath and an exterior sheath. Each of these sheaths comprises an electrode which is annular in shape and to which a suitable RF voltage can be applied. Consequently, this is a bipolar electrosurgical instrument. For connecting the ends or end sections of a blood vessel, the first end is passed through the interior sheath and folded over in such a manner that the tissue comes to be placed on the outside of the interior sheath. The second end of the vessel is pulled over the interior sheath and pulled onto the end section of the blood vessel located thereon. The exterior sheath can be opened and slipped over the interior sheath and the tissue located thereon. Consequently, the exterior sheath forms a type of cuff that encloses the individual end sections of the blood vessel. Both the interior sheath and the exterior sheath have an electrode for the application of the RF current. These electrodes are located opposite each other. When the RF current is being applied it flows through the tissue, i.e., the superimposed end sections, thus welding the vessel in place. One problem of the technique described in WO 03/061487 A1 is that the produced connections are frequently not sufficiently stable.